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<html lang="en">

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    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>在数组的开头添加新元素 - unshift()</title>
</head>

<body>
    <p id="demo">单击按钮在数组中插入元素。</p>
    <button onclick="myFunction()">点我</button>
    <script>
        function myFunction() {
            var fruits = ["Banana", "Orange", "Apple", "Mango"];
            fruits.unshift("Lemon", "Pineapple");
            var x = document.getElementById("demo");
            x.innerHTML = fruits;
        }
    </script>
    <p><b>注意:</b> unshift()方法不能用于 Internet Explorer 8 之前的版本，插入的值将被返回成<em> undefined </em>。</p>
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